Microprocessors or digital signal processors (DSPs) have conventionally been used to control electric motors. When software is coded using a microprocessor or a DSP, software designers need to be technologically sophisticated since various function blocks for vector control need to be converted into software. Accordingly, a development period and achievement of specification requirement depend upon designer's skill, software programming and/or an experience point of coding.
Techniques of configuring an entire motor control sequence into hardware have been developed in order to overcome the above-described problem. For example, a plurality of operation control modules is configured by digital hardware by means of z transformation. An electric motor is controlled by a sequencer which executes these operation control modules and the like in a predetermined sequence. In this case, no software needs to be developed, and the number of parameters to be set is reduced. Accordingly, the motor can be controlled easily. Moreover, the motor control is executed at higher speeds than by a software configuration. However, since the modules executing the control operation are configured into hardware by the above-described technique, particular functions desired by a user using a motor control device cannot be added. Thus, the above-described technique is difficult to apply to products which necessitate the peculiar processes.